Workaround for Bug 623: Sporadic XCB assertion failures w/ ATI proprietary driver and w/o native X11 locking

The proprietary ATI X11 driver does not handle multi-threaded [GL] clients well,
i.e. triggers an XCB assertion 'from time to time'.

It almost seems like that the driver either:
  - aliases all display connections to it's connection name, i.e. server; or
  - utilizes a build-in display connection w/o locking, used for some reason

+++

- X11Lib: Add QueryExtension(dpy, name) allowing early driver determination w/o GL

- X11Util detects 'requiresGlobalToolkitLock' and 'markAllDisplaysUnclosable' via
  X11 extensions. In case certain ATI extensions are available, both are set to true.

- X11GLXDrawableFactory: Dropped setting 'markAllDisplaysUnclosable', using X11Util's detection (see above).

- New GlobalToolkitLock to satisfy certain driver restrictions (ATI's XCB multithreading bug)

- NativeWindowFactory handles new property requiresGlobalToolkitLock,
  in which case the new GlobalToolkitLock is being used instead of ResourceToolkitLock.

- JAWTUtil ToolkitLock locks GlobalToolkitLock 1st to match new 'requiresGlobalToolkitLock' property.

- Document static method requirement of X11Util, GDIUtil and OSXUtil via marker interface ToolkitProperties

- ToolkitLock: New method 'validateLocked()', allowing use to validate whether the device/toolkit
  is properly locked and hence to detect implementation bugs. See unit test class: ValidateLockListener

21 files changed, 496 insertions, 88 deletions

diff --git a/make/config/nativewindow/x11-CustomJavaCode.java b/make/config/nativewindow/x11-CustomJavaCode.java
index 56aec4725..8e5da3b2d 100644
--- a/make/config/nativewindow/x11-CustomJavaCode.java
+++ b/make/config/nativewindow/x11-CustomJavaCode.java
@@ -36,6 +36,11 @@
   }
   private static native Object GetRelativeLocation0(long display, int screen_index, long src_win, long dest_win, int src_x, int src_y);
 
+  public static boolean QueryExtension(long display, String extensionName) {
+    return QueryExtension0(display, extensionName);
+  }
+  private static native boolean QueryExtension0(long display, String extensionName);
+
   public static native int XCloseDisplay(long display);
   public static native void XUnlockDisplay(long display);
   public static native void XLockDisplay(long display);
diff --git a/make/scripts/tests.sh b/make/scripts/tests.sh
index 345e23ae7..0908ef1fd 100755
--- a/make/scripts/tests.sh
+++ b/make/scripts/tests.sh
@@ -137,7 +137,8 @@ function jrun() {
     #D_ARGS="-Dnativewindow.debug=all"
     #D_ARGS="-Djogl.debug.GLCanvas"
     #D_ARGS="-Djogl.debug.GLContext -Dnativewindow.debug.X11Util.XSync"
-    #D_ARGS="-Dnativewindow.debug.X11Util.XSync"
+    #D_ARGS="-Dnativewindow.debug.X11Util.XSync -Dnativewindow.debug.ToolkitLock.TraceLock"
+    D_ARGS="-Dnativewindow.debug.X11Util -Dnativewindow.debug.X11Util.XSync -Dnativewindow.debug.NullToolkitLock.InvalidLocked -Dnativewindow.debug.NativeWindow"
     #D_ARGS="-Dnativewindow.debug.ToolkitLock"
     #D_ARGS="-Djogl.debug.graph.curve -Djogl.debug.GLSLCode -Djogl.debug.TraceGL"
     #D_ARGS="-Djogl.debug.graph.curve -Djogl.debug.GLSLState"
@@ -245,7 +246,7 @@ function testawtswt() {
 #testnoawt com.jogamp.opengl.test.junit.jogl.acore.TestGLProfile01NEWT $*
 #testnoawt com.jogamp.opengl.test.junit.jogl.acore.TestShutdownCompleteNEWT $*
 #testnoawt com.jogamp.opengl.test.junit.jogl.acore.TestInitConcurrent01NEWT $*
-#testnoawt com.jogamp.opengl.test.junit.jogl.acore.TestInitConcurrent02NEWT $*
+testnoawt com.jogamp.opengl.test.junit.jogl.acore.TestInitConcurrent02NEWT $*
 #testnoawt com.jogamp.opengl.test.junit.jogl.acore.TestGLContextSurfaceLockNEWT $*
 #testnoawt com.jogamp.opengl.test.junit.jogl.acore.TestGLDebug00NEWT $*
 #testnoawt com.jogamp.opengl.test.junit.jogl.acore.TestGLDebug01NEWT $*
@@ -254,7 +255,8 @@ function testawtswt() {
 #testnoawt com.jogamp.opengl.test.junit.jogl.acore.TestSharedContextVBOES1NEWT $*
 #testnoawt com.jogamp.opengl.test.junit.jogl.acore.TestSharedContextVBOES2NEWT $*
 #testnoawt com.jogamp.opengl.test.junit.jogl.acore.TestGLAutoDrawableDelegateNEWT $*
-testnoawt com.jogamp.opengl.test.junit.jogl.acore.TestGLContextDrawableSwitchNEWT $*
+#testnoawt com.jogamp.opengl.test.junit.jogl.acore.TestGLContextDrawableSwitchNEWT $*
+#testnoawt com.jogamp.opengl.test.junit.jogl.acore.TestBug623ATIXCBAssertionFailureNEWT $*
 
 #testnoawt com.jogamp.opengl.test.junit.jogl.acore.TestGLAutoDrawableDelegateOnOffscrnCapsNEWT $*
 #testnoawt com.jogamp.opengl.test.junit.jogl.acore.TestGLAutoDrawableGLWindowOnOffscrnCapsNEWT $*
diff --git a/src/jogl/classes/jogamp/opengl/x11/glx/X11GLXDrawableFactory.java b/src/jogl/classes/jogamp/opengl/x11/glx/X11GLXDrawableFactory.java
index b867125ad..018f6a6ea 100644
--- a/src/jogl/classes/jogamp/opengl/x11/glx/X11GLXDrawableFactory.java
+++ b/src/jogl/classes/jogamp/opengl/x11/glx/X11GLXDrawableFactory.java
@@ -241,10 +241,6 @@ public class X11GLXDrawableFactory extends GLDrawableFactoryImpl {
                 final String glXServerVendorName = GLX.glXQueryServerString(sharedDevice.getHandle(), 0, GLX.GLX_VENDOR);
                 final VersionNumber glXServerVersion = GLXUtil.getGLXServerVersionNumber(sharedDevice);
                 final boolean glXServerMultisampleAvailable = GLXUtil.isMultisampleAvailable(GLX.glXQueryServerString(sharedDevice.getHandle(), 0, GLX.GLX_EXTENSIONS));
-                if(X11Util.ATI_HAS_XCLOSEDISPLAY_BUG && GLXUtil.isVendorATI(glXServerVendorName)) {
-                    X11Util.setMarkAllDisplaysUnclosable(true);
-                    X11Util.markDisplayUncloseable(sharedDevice.getHandle());
-                }
                 
                 final GLProfile glp = GLProfile.get(sharedDevice, GLProfile.GL_PROFILE_LIST_MIN_DESKTOP, false);
                 if (null == glp) {
diff --git a/src/nativewindow/classes/com/jogamp/nativewindow/x11/X11GraphicsDevice.java b/src/nativewindow/classes/com/jogamp/nativewindow/x11/X11GraphicsDevice.java
index 142bb99e3..0f28ca67c 100644
--- a/src/nativewindow/classes/com/jogamp/nativewindow/x11/X11GraphicsDevice.java
+++ b/src/nativewindow/classes/com/jogamp/nativewindow/x11/X11GraphicsDevice.java
@@ -61,7 +61,7 @@ public class X11GraphicsDevice extends DefaultGraphicsDevice implements Cloneabl
     }
 
     /** Constructs a new X11GraphicsDevice corresponding to the given native display handle and default
-     *  {@link javax.media.nativewindow.ToolkitLock} via {@link NativeWindowFactory#createDefaultToolkitLock(String, long)}.
+     *  {@link javax.media.nativewindow.ToolkitLock} via {@link NativeWindowFactory#getDefaultToolkitLock(String, long)}.
      *  @see DefaultGraphicsDevice#DefaultGraphicsDevice(String, String, int, long)
      */
     public X11GraphicsDevice(long display, int unitID, boolean owner) {
diff --git a/src/nativewindow/classes/javax/media/nativewindow/AbstractGraphicsDevice.java b/src/nativewindow/classes/javax/media/nativewindow/AbstractGraphicsDevice.java
index 5eaaa6613..8ecd5242d 100644
--- a/src/nativewindow/classes/javax/media/nativewindow/AbstractGraphicsDevice.java
+++ b/src/nativewindow/classes/javax/media/nativewindow/AbstractGraphicsDevice.java
@@ -102,17 +102,24 @@ public interface AbstractGraphicsDevice extends Cloneable {
     public long getHandle();
 
     /**
-     * Optionally locking the device, utilizing eg {@link javax.media.nativewindow.ToolkitLock}.
+     * Optionally locking the device, utilizing eg {@link javax.media.nativewindow.ToolkitLock#lock()}.
      * The lock implementation must be recursive.
      */
     public void lock();
 
     /** 
-     * Optionally unlocking the device, utilizing eg {@link javax.media.nativewindow.ToolkitLock}.
+     * Optionally unlocking the device, utilizing eg {@link javax.media.nativewindow.ToolkitLock#unlock()}.
      * The lock implementation must be recursive.
+     * 
+     * @throws RuntimeException in case the lock is not acquired by this thread.
      */
     public void unlock();
 
+    /**
+     * @throws RuntimeException if current thread does not hold the lock 
+     */
+    public void validateLocked() throws RuntimeException;
+    
     /** 
      * Optionally [re]opening the device if handle is <code>null</code>.
      * <p>
diff --git a/src/nativewindow/classes/javax/media/nativewindow/DefaultGraphicsDevice.java b/src/nativewindow/classes/javax/media/nativewindow/DefaultGraphicsDevice.java
index b16b0c75c..9288652d9 100644
--- a/src/nativewindow/classes/javax/media/nativewindow/DefaultGraphicsDevice.java
+++ b/src/nativewindow/classes/javax/media/nativewindow/DefaultGraphicsDevice.java
@@ -60,7 +60,7 @@ public class DefaultGraphicsDevice implements Cloneable, AbstractGraphicsDevice
 
     /**
      * Create an instance with the system default {@link ToolkitLock}.
-     * gathered via {@link NativeWindowFactory#createDefaultToolkitLock(String, long)}.
+     * gathered via {@link NativeWindowFactory#getDefaultToolkitLock(String, long)}.
      * @param type
      * @param handle
      */
@@ -70,7 +70,7 @@ public class DefaultGraphicsDevice implements Cloneable, AbstractGraphicsDevice
         this.unitID = unitID;
         this.uniqueID = getUniqueID(type, connection, unitID);
         this.handle = handle;
-        this.toolkitLock = NativeWindowFactory.createDefaultToolkitLock(type, handle);
+        this.toolkitLock = NativeWindowFactory.getDefaultToolkitLock(type, handle);
     }
 
     /**
@@ -123,8 +123,10 @@ public class DefaultGraphicsDevice implements Cloneable, AbstractGraphicsDevice
     }
 
     /**
-     * No lock is performed on the graphics device per default,
-     * instead the aggregated recursive {@link ToolkitLock#lock()} is invoked.
+     * {@inheritDoc}
+     * <p>
+     * Locking is perfomed via delegation to {@link ToolkitLock#lock()}, {@link ToolkitLock#unlock()}.
+     * </p>
      *
      * @see DefaultGraphicsDevice#DefaultGraphicsDevice(java.lang.String, long)
      * @see DefaultGraphicsDevice#DefaultGraphicsDevice(java.lang.String, long, javax.media.nativewindow.ToolkitLock)
@@ -134,9 +136,16 @@ public class DefaultGraphicsDevice implements Cloneable, AbstractGraphicsDevice
         toolkitLock.lock();
     }
 
+    @Override
+    public final void validateLocked() throws RuntimeException {
+        toolkitLock.validateLocked();
+    }
+    
     /** 
-     * No lock is performed on the graphics device per default,
-     * instead the aggregated recursive {@link ToolkitLock#unlock()} is invoked.
+     * {@inheritDoc}
+     * <p>
+     * Locking is perfomed via delegation to {@link ToolkitLock#lock()}, {@link ToolkitLock#unlock()}.
+     * </p>
      *
      * @see DefaultGraphicsDevice#DefaultGraphicsDevice(java.lang.String, long)
      * @see DefaultGraphicsDevice#DefaultGraphicsDevice(java.lang.String, long, javax.media.nativewindow.ToolkitLock)
diff --git a/src/nativewindow/classes/javax/media/nativewindow/NativeWindowFactory.java b/src/nativewindow/classes/javax/media/nativewindow/NativeWindowFactory.java
index 4f4bb629b..af8008f0f 100644
--- a/src/nativewindow/classes/javax/media/nativewindow/NativeWindowFactory.java
+++ b/src/nativewindow/classes/javax/media/nativewindow/NativeWindowFactory.java
@@ -42,6 +42,7 @@ import java.util.Map;
 
 import jogamp.nativewindow.Debug;
 import jogamp.nativewindow.NativeWindowFactoryImpl;
+import jogamp.nativewindow.ToolkitProperties;
 import jogamp.nativewindow.ResourceToolkitLock;
 
 import com.jogamp.common.os.Platform;
@@ -87,13 +88,17 @@ public abstract class NativeWindowFactory {
     private static boolean isAWTAvailable;
     
     private static final String JAWTUtilClassName = "jogamp.nativewindow.jawt.JAWTUtil" ;
+    /** {@link jogamp.nativewindow.x11.X11Util} implements {@link ToolkitProperties}. */
     private static final String X11UtilClassName = "jogamp.nativewindow.x11.X11Util";
+    /** {@link jogamp.nativewindow.macosx.OSXUtil} implements {@link ToolkitProperties}. */
     private static final String OSXUtilClassName = "jogamp.nativewindow.macosx.OSXUtil";
+    /** {@link jogamp.nativewindow.windows.GDIUtil} implements {@link ToolkitProperties}. */
     private static final String GDIClassName = "jogamp.nativewindow.windows.GDIUtil";
     
     private static ToolkitLock jawtUtilJAWTToolkitLock;
     
     private static boolean requiresToolkitLock;
+    private static boolean requiresGlobalToolkitLock;
 
     private static volatile boolean isJVMShuttingDown = false;
     
@@ -156,11 +161,18 @@ public abstract class NativeWindowFactory {
         if( null != clazzName ) {
             ReflectionUtil.callStaticMethod(clazzName, "initSingleton", null, null, cl );
             
-            final Boolean res = (Boolean) ReflectionUtil.callStaticMethod(clazzName, "requiresToolkitLock", null, null, cl);
-            requiresToolkitLock = res.booleanValue();             
+            final Boolean res1 = (Boolean) ReflectionUtil.callStaticMethod(clazzName, "requiresToolkitLock", null, null, cl);
+            requiresToolkitLock = res1.booleanValue();
+            if(requiresToolkitLock) {
+                final Boolean res2 = (Boolean) ReflectionUtil.callStaticMethod(clazzName, "requiresGlobalToolkitLock", null, null, cl);
+                requiresGlobalToolkitLock = res2.booleanValue();
+            } else {
+                requiresGlobalToolkitLock = false;
+            }
         } else {            
             requiresToolkitLock = false;
-        }        
+            requiresGlobalToolkitLock = false;
+        }
     }
 
     private static void shutdownNativeImpl(final ClassLoader cl) {
@@ -261,7 +273,7 @@ public abstract class NativeWindowFactory {
             }
             
             if(DEBUG) {
-                System.err.println("NativeWindowFactory requiresToolkitLock "+requiresToolkitLock);
+                System.err.println("NativeWindowFactory requiresToolkitLock "+requiresToolkitLock+", requiresGlobalToolkitLock "+requiresGlobalToolkitLock);
                 System.err.println("NativeWindowFactory isAWTAvailable "+isAWTAvailable+", defaultFactory "+factory);
             }
             
@@ -295,7 +307,12 @@ public abstract class NativeWindowFactory {
     /** @return true if the underlying toolkit requires locking, otherwise false. */
     public static boolean requiresToolkitLock() {
         return requiresToolkitLock;
-    }    
+    }
+    
+    /** @return true if the underlying toolkit requires global locking, otherwise false. */
+    public static boolean requiresGlobalToolkitLock() {
+        return requiresGlobalToolkitLock;
+    }
     
     /** @return true if not headless, AWT Component and NativeWindow's AWT part available */
     public static boolean isAWTAvailable() { return isAWTAvailable; }
@@ -331,9 +348,28 @@ public abstract class NativeWindowFactory {
         return defaultFactory;
     }
 
+    /** 
+     * Returns the AWT {@link ToolkitLock} (JAWT based) if {@link #isAWTAvailable}, otherwise null.
+     * <p>
+     * The JAWT based {@link ToolkitLock} also locks the global lock,
+     * which matters if the latter is required.
+     * </p> 
+     */ 
+    public static ToolkitLock getAWTToolkitLock() {
+        return jawtUtilJAWTToolkitLock;
+    }
+
+    public static ToolkitLock getNullToolkitLock() {
+        return NativeWindowFactoryImpl.getNullToolkitLock();
+    }
+
+    public static ToolkitLock getGlobalToolkitLock() {
+        return NativeWindowFactoryImpl.getGlobalToolkitLock();
+    }
+    
     /**
-     * Provides the system default {@link ToolkitLock}, a singleton instance.
-     * <br>
+     * Provides the system default {@link ToolkitLock} for the default system windowing type.
+     * @see #getNativeWindowType(boolean)
      * @see #getDefaultToolkitLock(java.lang.String)
      */
     public static ToolkitLock getDefaultToolkitLock() {
@@ -341,57 +377,44 @@ public abstract class NativeWindowFactory {
     }
 
     /**
-     * Provides the default {@link ToolkitLock} for <code>type</code>, a singleton instance.
+     * Provides the default {@link ToolkitLock} for <code>type</code>.
      * <ul>
-     *   <li> JAWT {@link ToolkitLock} if required and AWT available, otherwise</li>
+     *   <li> JAWT {@link ToolkitLock} if required and <code>type</code> is of {@link #TYPE_AWT} and AWT available,</li>
+     *   <li> {@link jogamp.nativewindow.GlobalToolkitLock} if required, otherwise</li>
+     *   <li> {@link jogamp.nativewindow.ResourceToolkitLock} if required, otherwise</li>
      *   <li> {@link jogamp.nativewindow.NullToolkitLock} </li>
      * </ul>
      */
     public static ToolkitLock getDefaultToolkitLock(String type) {
-        if( requiresToolkitLock() ) {
-            if( TYPE_AWT == type && TYPE_X11 == getNativeWindowType(false) && isAWTAvailable() ) {
+        if( requiresToolkitLock ) {
+            if( TYPE_AWT == type && isAWTAvailable() ) {
                 return getAWTToolkitLock();
             }
-        }
-        return NativeWindowFactoryImpl.getNullToolkitLock();
-    }
-
-    /** Returns the AWT Toolkit (JAWT based) if {@link #isAWTAvailable}, otherwise null. */ 
-    public static ToolkitLock getAWTToolkitLock() {
-        return jawtUtilJAWTToolkitLock;
-    }
-
-    public static ToolkitLock getNullToolkitLock() {
-        return NativeWindowFactoryImpl.getNullToolkitLock();
-    }
-
-    /**
-     * Creates the default {@link ToolkitLock} for <code>type</code> and <code>deviceHandle</code>.
-     * <ul>
-     *   <li> {@link jogamp.nativewindow.ResourceToolkitLock} if required, otherwise</li>
-     *   <li> {@link jogamp.nativewindow.NullToolkitLock} </li>
-     * </ul>
-     */
-    public static ToolkitLock createDefaultToolkitLock(String type, long deviceHandle) {
-        if( requiresToolkitLock() ) {
+            if( requiresGlobalToolkitLock ) {
+                return NativeWindowFactoryImpl.getGlobalToolkitLock();
+            }
             return ResourceToolkitLock.create();
         }
         return NativeWindowFactoryImpl.getNullToolkitLock();
     }
-    
+
     /**
-     * Creates the default {@link ToolkitLock} for <code>type</code> and <code>deviceHandle</code>.
+     * Provides the default {@link ToolkitLock} for <code>type</code> and <code>deviceHandle</code>.
      * <ul>
-     *   <li> JAWT {@link ToolkitLock} if required and AWT available,</li>
+     *   <li> JAWT {@link ToolkitLock} if required and <code>type</code> is of {@link #TYPE_AWT} and AWT available,</li>
+     *   <li> {@link jogamp.nativewindow.GlobalToolkitLock} if required, otherwise</li>
      *   <li> {@link jogamp.nativewindow.ResourceToolkitLock} if required, otherwise</li>
      *   <li> {@link jogamp.nativewindow.NullToolkitLock} </li>
      * </ul>
      */
-    public static ToolkitLock createDefaultToolkitLock(String type, String sharedType, long deviceHandle) {
-        if( requiresToolkitLock() ) {
-            if( TYPE_AWT == sharedType && isAWTAvailable() ) {
+    public static ToolkitLock getDefaultToolkitLock(String type, long deviceHandle) {
+        if( requiresToolkitLock ) {
+            if( TYPE_AWT == type && isAWTAvailable() ) {
                 return getAWTToolkitLock();
             }
+            if( requiresGlobalToolkitLock ) {
+                return NativeWindowFactoryImpl.getGlobalToolkitLock();
+            }
             return ResourceToolkitLock.create();
         }
         return NativeWindowFactoryImpl.getNullToolkitLock();
diff --git a/src/nativewindow/classes/javax/media/nativewindow/ToolkitLock.java b/src/nativewindow/classes/javax/media/nativewindow/ToolkitLock.java
index 18b7cf5d9..eccfcfa4f 100644
--- a/src/nativewindow/classes/javax/media/nativewindow/ToolkitLock.java
+++ b/src/nativewindow/classes/javax/media/nativewindow/ToolkitLock.java
@@ -37,15 +37,35 @@ import jogamp.nativewindow.Debug;
  * Toolkit locks are created solely via {@link NativeWindowFactory}.
  * </p>
  * <p>
- * One use case is the AWT locking on X11, see {@link NativeWindowFactory#createDefaultToolkitLock(String, long)}.
+ * One use case is the AWT locking on X11, see {@link NativeWindowFactory#getDefaultToolkitLock(String, long)}.
  * </p>
  */
 public interface ToolkitLock {
+    public static final boolean DEBUG = Debug.debug("ToolkitLock");
     public static final boolean TRACE_LOCK = Debug.isPropertyDefined("nativewindow.debug.ToolkitLock.TraceLock", true);
 
+    /**
+     * Blocking until the lock is acquired by this Thread or a timeout is reached.
+     * <p>
+     * Timeout is implementation specific, if used at all.
+     * </p>
+     *
+     * @throws RuntimeException in case of a timeout
+     */
     public void lock();
+    
+    /**
+     * Release the lock.
+     *
+     * @throws RuntimeException in case the lock is not acquired by this thread.
+     */
     public void unlock();
     
+    /**
+     * @throws RuntimeException if current thread does not hold the lock 
+     */
+    public void validateLocked() throws RuntimeException;
+    
     /** 
      * Dispose this instance.
      * <p> 
diff --git a/src/nativewindow/classes/jogamp/nativewindow/GlobalToolkitLock.java b/src/nativewindow/classes/jogamp/nativewindow/GlobalToolkitLock.java
new file mode 100644
index 000000000..0c2a1e43f
--- /dev/null
+++ b/src/nativewindow/classes/jogamp/nativewindow/GlobalToolkitLock.java
@@ -0,0 +1,75 @@
+/**
+ * Copyright 2012 JogAmp Community. All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without modification, are
+ * permitted provided that the following conditions are met:
+ *
+ *    1. Redistributions of source code must retain the above copyright notice, this list of
+ *       conditions and the following disclaimer.
+ *
+ *    2. Redistributions in binary form must reproduce the above copyright notice, this list
+ *       of conditions and the following disclaimer in the documentation and/or other materials
+ *       provided with the distribution.
+ *
+ * THIS SOFTWARE IS PROVIDED BY JogAmp Community ``AS IS'' AND ANY EXPRESS OR IMPLIED
+ * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND
+ * FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL JogAmp Community OR
+ * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
+ * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
+ * SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON
+ * ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
+ * NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF
+ * ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ *
+ * The views and conclusions contained in the software and documentation are those of the
+ * authors and should not be interpreted as representing official policies, either expressed
+ * or implied, of JogAmp Community.
+ */
+
+package jogamp.nativewindow;
+
+import javax.media.nativewindow.ToolkitLock;
+
+import com.jogamp.common.util.locks.LockFactory;
+import com.jogamp.common.util.locks.RecursiveLock;
+
+/**
+ * Implementing a global recursive {@link javax.media.nativewindow.ToolkitLock}.
+ * <p>
+ * This is the last resort for unstable driver, e.g. proprietary ATI/X11 12.8 and 12.9,
+ * where multiple X11 display connections to the same connection name are not treated
+ * thread safe within the GL/X11 driver.
+ * </p>
+ */
+public class GlobalToolkitLock implements ToolkitLock {
+    private static final RecursiveLock globalLock = LockFactory.createRecursiveLock();
+    
+    /** Singleton via {@link NativeWindowFactoryImpl#getGlobalToolkitLock()} */
+    protected GlobalToolkitLock() { }
+    
+    @Override
+    public final void lock() {
+        globalLock.lock();
+        if(TRACE_LOCK) { System.err.println("GlobalToolkitLock.lock()"); }
+    }
+
+    @Override
+    public final void unlock() {
+        if(TRACE_LOCK) { System.err.println("GlobalToolkitLock.unlock()"); }
+        globalLock.unlock(); // implicit lock validation
+    }
+    
+    @Override
+    public final void validateLocked() throws RuntimeException {
+        globalLock.validateLocked();
+    }
+    
+    @Override
+    public final void dispose() {
+        // nop
+    }
+    
+    public String toString() {
+        return "GlobalToolkitLock[obj 0x"+Integer.toHexString(hashCode())+", isOwner "+globalLock.isOwner(Thread.currentThread())+", "+globalLock.toString()+"]";
+    }
+}
diff --git a/src/nativewindow/classes/jogamp/nativewindow/NativeWindowFactoryImpl.java b/src/nativewindow/classes/jogamp/nativewindow/NativeWindowFactoryImpl.java
index 29564da3b..c35cede77 100644
--- a/src/nativewindow/classes/jogamp/nativewindow/NativeWindowFactoryImpl.java
+++ b/src/nativewindow/classes/jogamp/nativewindow/NativeWindowFactoryImpl.java
@@ -44,9 +44,14 @@ import com.jogamp.common.util.ReflectionUtil.AWTNames;
 
 public class NativeWindowFactoryImpl extends NativeWindowFactory {
     private static final ToolkitLock nullToolkitLock = new NullToolkitLock();
+    private static final ToolkitLock globalToolkitLock = new GlobalToolkitLock();
 
     public static ToolkitLock getNullToolkitLock() {
-            return nullToolkitLock;
+        return nullToolkitLock;
+    }
+    
+    public static ToolkitLock getGlobalToolkitLock() {
+        return globalToolkitLock;
     }
     
     // This subclass of NativeWindowFactory handles the case of
diff --git a/src/nativewindow/classes/jogamp/nativewindow/NullToolkitLock.java b/src/nativewindow/classes/jogamp/nativewindow/NullToolkitLock.java
index e59910138..211e15955 100644
--- a/src/nativewindow/classes/jogamp/nativewindow/NullToolkitLock.java
+++ b/src/nativewindow/classes/jogamp/nativewindow/NullToolkitLock.java
@@ -31,15 +31,16 @@ package jogamp.nativewindow;
 import javax.media.nativewindow.ToolkitLock;
 
 /**
- * Implementing a singleton global recursive {@link javax.media.nativewindow.ToolkitLock}
- * without any locking. Since there is no locking it all,
- * it is intrinsically recursive.
+ * Implementing a singleton global NOP {@link javax.media.nativewindow.ToolkitLock}
+ * without any locking. Since there is no locking it all, it is intrinsically recursive.
  */
 public class NullToolkitLock implements ToolkitLock {
-
+    public static final boolean INVALID_LOCKED = Debug.isPropertyDefined("nativewindow.debug.NullToolkitLock.InvalidLocked", true);
+    
     /** Singleton via {@link NativeWindowFactoryImpl#getNullToolkitLock()} */
     protected NullToolkitLock() { }
     
+    @Override
     public final void lock() {
         if(TRACE_LOCK) {
             System.err.println("NullToolkitLock.lock()");
@@ -47,10 +48,20 @@ public class NullToolkitLock implements ToolkitLock {
         }
     }
 
+    @Override
     public final void unlock() {
         if(TRACE_LOCK) { System.err.println("NullToolkitLock.unlock()"); }
     }
     
+    @Override
+    public final void validateLocked() throws RuntimeException {
+        /* nop */
+        if(INVALID_LOCKED) {
+            throw new RuntimeException("NullToolkitLock does not lock");
+        }
+    }
+    
+    @Override
     public final void dispose() {
         // nop
     }
diff --git a/src/nativewindow/classes/jogamp/nativewindow/ResourceToolkitLock.java b/src/nativewindow/classes/jogamp/nativewindow/ResourceToolkitLock.java
index a3b0804fa..5b79de0b8 100644
--- a/src/nativewindow/classes/jogamp/nativewindow/ResourceToolkitLock.java
+++ b/src/nativewindow/classes/jogamp/nativewindow/ResourceToolkitLock.java
@@ -41,8 +41,6 @@ import com.jogamp.common.util.locks.RecursiveLock;
  * </p>
  */
 public class ResourceToolkitLock implements ToolkitLock {
-    public static final boolean DEBUG = Debug.debug("ToolkitLock");
-    
     public static final ResourceToolkitLock create() {
         return new ResourceToolkitLock();
     }
@@ -53,17 +51,24 @@ public class ResourceToolkitLock implements ToolkitLock {
         this.lock = LockFactory.createRecursiveLock();
     }
     
-    
+    @Override
     public final void lock() {
-        if(TRACE_LOCK) { System.err.println("ResourceToolkitLock.lock()"); }
         lock.lock();
+        if(TRACE_LOCK) { System.err.println("ResourceToolkitLock.lock()"); }
     }
 
+    @Override
     public final void unlock() {
         if(TRACE_LOCK) { System.err.println("ResourceToolkitLock.unlock()"); }
-        lock.unlock();
+        lock.unlock(); // implicit lock validation
+    }
+    
+    @Override
+    public final void validateLocked() throws RuntimeException {
+        lock.validateLocked();
     }
     
+    @Override
     public final void dispose() {
         // nop
     }
diff --git a/src/nativewindow/classes/jogamp/nativewindow/SharedResourceToolkitLock.java b/src/nativewindow/classes/jogamp/nativewindow/SharedResourceToolkitLock.java
index 5d7ae8abb..94d12e6fc 100644
--- a/src/nativewindow/classes/jogamp/nativewindow/SharedResourceToolkitLock.java
+++ b/src/nativewindow/classes/jogamp/nativewindow/SharedResourceToolkitLock.java
@@ -49,7 +49,6 @@ import com.jogamp.common.util.locks.RecursiveLock;
  * </p>
  */
 public class SharedResourceToolkitLock implements ToolkitLock {
-    public static final boolean DEBUG = Debug.debug("ToolkitLock");
     private static final LongObjectHashMap handle2Lock;
     static {
         handle2Lock = new LongObjectHashMap();
@@ -109,16 +108,24 @@ public class SharedResourceToolkitLock implements ToolkitLock {
     }
     
     
+    @Override
     public final void lock() {
-        if(TRACE_LOCK) { System.err.println("SharedResourceToolkitLock.lock()"); }
         lock.lock();
+        if(TRACE_LOCK) { System.err.println("SharedResourceToolkitLock.lock()"); }
     }
 
+    @Override
     public final void unlock() {
         if(TRACE_LOCK) { System.err.println("SharedResourceToolkitLock.unlock()"); }
         lock.unlock();
     }
     
+    @Override
+    public final void validateLocked() throws RuntimeException {
+        lock.validateLocked();
+    }
+    
+    @Override
     public final void dispose() {
         if(0 < refCount) { // volatile OK
             synchronized(handle2Lock) {
diff --git a/src/nativewindow/classes/jogamp/nativewindow/ToolkitProperties.java b/src/nativewindow/classes/jogamp/nativewindow/ToolkitProperties.java
new file mode 100644
index 000000000..2062d1f58
--- /dev/null
+++ b/src/nativewindow/classes/jogamp/nativewindow/ToolkitProperties.java
@@ -0,0 +1,51 @@
+package jogamp.nativewindow;
+
+import javax.media.nativewindow.NativeWindowFactory;
+
+/**
+ * Marker interface.
+ * <p>
+ * Implementation requires to provide static methods:
+ * <pre>
+    public static void initSingleton() {}
+    
+    public static void shutdown() {}
+    
+    public static boolean requiresToolkitLock() {}
+    
+    public static boolean requiresGlobalToolkitLock() {}
+ * </pre>
+ * Above static methods are invoked by {@link NativeWindowFactory#initSingleton()}, 
+ * or {@link NativeWindowFactory#shutdown()} via reflection.
+ * </p>
+ * <p>
+ * If <code>requiresGlobalToolkitLock() == true</code>, then 
+ * <code>requiresToolkitLock() == true</code> shall be valid as well.
+ * </p>
+ */
+public interface ToolkitProperties {
+
+    /**
+     * Called by {@link NativeWindowFactory#initSingleton()}
+     */
+    // void initSingleton();
+    
+    /** 
+     * Cleanup resources.
+     * <p>
+     * Called by {@link NativeWindowFactory#shutdown()}
+     * </p>
+     */
+    // void shutdown();
+    
+    /**
+     * Called by {@link NativeWindowFactory#initSingleton()}
+     */
+    // boolean requiresToolkitLock();
+    
+    /**
+     * Called by {@link NativeWindowFactory#initSingleton()}
+     */
+    // boolean requiresGlobalToolkitLock();    
+    
+}
diff --git a/src/nativewindow/classes/jogamp/nativewindow/jawt/JAWTUtil.java b/src/nativewindow/classes/jogamp/nativewindow/jawt/JAWTUtil.java
index 7c934b154..2dadfb16b 100644
--- a/src/nativewindow/classes/jogamp/nativewindow/jawt/JAWTUtil.java
+++ b/src/nativewindow/classes/jogamp/nativewindow/jawt/JAWTUtil.java
@@ -79,6 +79,8 @@ public class JAWTUtil {
   private static final Method  sunToolkitAWTLockMethod;
   private static final Method  sunToolkitAWTUnlockMethod;
   private static final boolean hasSunToolkitAWTLock;
+  
+  private static volatile Thread exclusiveOwnerThread;
 
   private static final ToolkitLock jawtToolkitLock;
 
@@ -229,13 +231,23 @@ public class JAWTUtil {
     }
     hasSunToolkitAWTLock = _hasSunToolkitAWTLock;
     // hasSunToolkitAWTLock = false;
+    exclusiveOwnerThread = null;
 
     jawtToolkitLock = new ToolkitLock() {
           public final void lock() {
+              NativeWindowFactory.getGlobalToolkitLock().lock();
               JAWTUtil.lockToolkit();
+              if(TRACE_LOCK) { System.err.println("JAWTToolkitLock.lock()"); }
           }    
           public final void unlock() {
+              if(TRACE_LOCK) { System.err.println("JAWTToolkitLock.unlock()"); }
               JAWTUtil.unlockToolkit();
+              NativeWindowFactory.getGlobalToolkitLock().unlock();
+          }
+          @Override
+          public final void validateLocked() throws RuntimeException {
+              NativeWindowFactory.getGlobalToolkitLock().validateLocked();
+              JAWTUtil.validateLocked();
           }
           public final void dispose() {
               // nop
@@ -312,7 +324,7 @@ public class JAWTUtil {
    * JAWT's native Lock() function calls SunToolkit.awtLock(),
    * which just uses AWT's global ReentrantLock.<br>
    */
-  private static void awtLock() {
+  private static final void awtLock() {
     if(hasSunToolkitAWTLock) {
         try {
             sunToolkitAWTLockMethod.invoke(null, (Object[])null);
@@ -322,6 +334,7 @@ public class JAWTUtil {
     } else {
         jawtLockObject.Lock();
     }
+    exclusiveOwnerThread = Thread.currentThread();
   }
 
   /**
@@ -330,7 +343,9 @@ public class JAWTUtil {
    * JAWT's native Unlock() function calls SunToolkit.awtUnlock(),
    * which just uses AWT's global ReentrantLock.<br>
    */
-  private static void awtUnlock() {
+  private static final void awtUnlock() {
+    awtValidateLocked();
+    exclusiveOwnerThread = null;    
     if(hasSunToolkitAWTLock) {
         try {
             sunToolkitAWTUnlockMethod.invoke(null, (Object[])null);
@@ -342,6 +357,16 @@ public class JAWTUtil {
     }
   }
 
+  private static final void awtValidateLocked() throws RuntimeException {
+    final Thread ct = Thread.currentThread();
+    if( ct != exclusiveOwnerThread ) {
+        if ( null == exclusiveOwnerThread ) {
+            throw new RuntimeException(ct.getName()+": JAWT-ToolkitLock not locked");
+        }
+        throw new RuntimeException(ct.getName()+": Not JAWT-ToolkitLock owner. Owner is "+exclusiveOwnerThread.getName());
+    }
+  }
+  
   public static void lockToolkit() throws NativeWindowException {
     if(ToolkitLock.TRACE_LOCK) { System.err.println("JAWTUtil-ToolkitLock.lock()"); }
     if(!headlessMode && !isJava2DQueueFlusherThread()) {
@@ -355,6 +380,13 @@ public class JAWTUtil {
         awtUnlock();
     }
   }
+  
+  public static final void validateLocked() throws RuntimeException {
+    if(!headlessMode && !isJava2DQueueFlusherThread()) {
+        awtValidateLocked();
+    }
+  }
+  
 
   public static ToolkitLock getJAWTToolkitLock() {
     return jawtToolkitLock;
diff --git a/src/nativewindow/classes/jogamp/nativewindow/macosx/OSXUtil.java b/src/nativewindow/classes/jogamp/nativewindow/macosx/OSXUtil.java
index b7a83e133..481cbbe39 100644
--- a/src/nativewindow/classes/jogamp/nativewindow/macosx/OSXUtil.java
+++ b/src/nativewindow/classes/jogamp/nativewindow/macosx/OSXUtil.java
@@ -34,13 +34,15 @@ import javax.media.nativewindow.util.Point;
 
 import jogamp.nativewindow.Debug;
 import jogamp.nativewindow.NWJNILibLoader;
+import jogamp.nativewindow.ToolkitProperties;
 
-public class OSXUtil {
+public class OSXUtil implements ToolkitProperties {
     private static boolean isInit = false;  
     private static final boolean DEBUG = Debug.debug("OSXUtil");
     
     /**
      * Called by {@link NativeWindowFactory#initSingleton()}
+     * @see ToolkitProperties
      */
     public static synchronized void initSingleton() {
       if(!isInit) {
@@ -60,13 +62,21 @@ public class OSXUtil {
 
     /**
      * Called by {@link NativeWindowFactory#shutdown()}
+     * @see ToolkitProperties
      */
-    public static void shutdown() {      
-    }
+    public static void shutdown() { }
     
-    public static boolean requiresToolkitLock() {
-        return false;
-    }
+    /**
+     * Called by {@link NativeWindowFactory#initSingleton()}
+     * @see ToolkitProperties
+     */
+    public static boolean requiresToolkitLock() { return false; }
+    
+    /**
+     * Called by {@link NativeWindowFactory#initSingleton()}
+     * @see ToolkitProperties
+     */
+    public static final boolean requiresGlobalToolkitLock() { return false; }
     
     public static boolean isNSView(long object) {
         return isNSView0(object);
diff --git a/src/nativewindow/classes/jogamp/nativewindow/windows/GDIUtil.java b/src/nativewindow/classes/jogamp/nativewindow/windows/GDIUtil.java
index 613c76032..4408a0903 100644
--- a/src/nativewindow/classes/jogamp/nativewindow/windows/GDIUtil.java
+++ b/src/nativewindow/classes/jogamp/nativewindow/windows/GDIUtil.java
@@ -33,9 +33,10 @@ import javax.media.nativewindow.NativeWindowFactory;
 
 import jogamp.nativewindow.NWJNILibLoader;
 import jogamp.nativewindow.Debug;
+import jogamp.nativewindow.ToolkitProperties;
 import jogamp.nativewindow.x11.X11Util;
 
-public class GDIUtil {
+public class GDIUtil implements ToolkitProperties {
     private static final boolean DEBUG = Debug.debug("GDIUtil");
   
     private static final String dummyWindowClassNameBase = "_dummyWindow_clazz" ;
@@ -44,6 +45,7 @@ public class GDIUtil {
   
     /**
      * Called by {@link NativeWindowFactory#initSingleton()}
+     * @see ToolkitProperties
      */
     public static synchronized void initSingleton() {
         if(!isInit) {
@@ -67,12 +69,23 @@ public class GDIUtil {
   
     /**
      * Called by {@link NativeWindowFactory#shutdown()}
+     * @see ToolkitProperties
      */
     public static void shutdown() {      
     }
     
+    /**
+     * Called by {@link NativeWindowFactory#initSingleton()}
+     * @see ToolkitProperties
+     */
     public static boolean requiresToolkitLock() { return false; }
   
+    /**
+     * Called by {@link NativeWindowFactory#initSingleton()}
+     * @see ToolkitProperties
+     */
+    public static final boolean requiresGlobalToolkitLock() { return false; }
+    
     private static RegisteredClass dummyWindowClass = null;
     private static Object dummyWindowSync = new Object();
   
diff --git a/src/nativewindow/classes/jogamp/nativewindow/x11/X11Util.java b/src/nativewindow/classes/jogamp/nativewindow/x11/X11Util.java
index 30792113d..a331fa940 100644
--- a/src/nativewindow/classes/jogamp/nativewindow/x11/X11Util.java
+++ b/src/nativewindow/classes/jogamp/nativewindow/x11/X11Util.java
@@ -43,13 +43,15 @@ import javax.media.nativewindow.NativeWindowFactory;
 
 import jogamp.nativewindow.Debug;
 import jogamp.nativewindow.NWJNILibLoader;
+import jogamp.nativewindow.ToolkitProperties;
+
 import com.jogamp.common.util.LongObjectHashMap;
 import com.jogamp.nativewindow.x11.X11GraphicsDevice;
 
 /**
  * Contains a thread safe X11 utility to retrieve display connections.
  */
-public class X11Util {
+public class X11Util implements ToolkitProperties {
     /** 
      * See Bug 515 - https://jogamp.org/bugzilla/show_bug.cgi?id=515
      * <p> 
@@ -88,11 +90,15 @@ public class X11Util {
     private static String nullDisplayName = null;
     private static volatile boolean isInit = false;
     private static boolean markAllDisplaysUnclosable = false; // ATI/AMD X11 driver issues
+    private static boolean requiresGlobalToolkitLock = false; // ATI/AMD X11 driver issues
 
     private static Object setX11ErrorHandlerLock = new Object();
+    private static final String X11_EXTENSION_ATIFGLRXDRI     = "ATIFGLRXDRI";
+    private static final String X11_EXTENSION_ATIFGLEXTENSION = "ATIFGLEXTENSION";
     
     /**
      * Called by {@link NativeWindowFactory#initSingleton()}
+     * @see ToolkitProperties
      */
     public static void initSingleton() {
         if(!isInit) {
@@ -100,7 +106,7 @@ public class X11Util {
                 if(!isInit) {
                     isInit = true;
                     if(DEBUG) {
-                        System.out.println("X11UtilUtil.initSingleton()");
+                        System.out.println("X11Util.initSingleton()");
                     }
                     if(!NWJNILibLoader.loadNativeWindow("x11")) {
                         throw new NativeWindowException("NativeWindow X11 native library load error.");
@@ -108,6 +114,7 @@ public class X11Util {
         
                     final boolean isInitOK = initialize0( XERROR_STACKDUMP );
         
+                    final boolean hasX11_EXTENSION_ATIFGLRXDRI, hasX11_EXTENSION_ATIFGLEXTENSION;
                     final long dpy = X11Lib.XOpenDisplay(null);
                     if(0 != dpy) {
                         if(XSYNC_ENABLED) {
@@ -115,17 +122,29 @@ public class X11Util {
                         }                    
                         try {
                             nullDisplayName = X11Lib.XDisplayString(dpy);
+                            hasX11_EXTENSION_ATIFGLRXDRI = X11Lib.QueryExtension(dpy, X11_EXTENSION_ATIFGLRXDRI);
+                            hasX11_EXTENSION_ATIFGLEXTENSION = X11Lib.QueryExtension(dpy, X11_EXTENSION_ATIFGLEXTENSION);
                         } finally {
                             X11Lib.XCloseDisplay(dpy);
                         }
                     } else {
                         nullDisplayName = "nil";
+                        hasX11_EXTENSION_ATIFGLRXDRI = false;
+                        hasX11_EXTENSION_ATIFGLEXTENSION = false;
                     }
+                    requiresGlobalToolkitLock = hasX11_EXTENSION_ATIFGLRXDRI || hasX11_EXTENSION_ATIFGLEXTENSION;
+                    markAllDisplaysUnclosable = ATI_HAS_XCLOSEDISPLAY_BUG && ( hasX11_EXTENSION_ATIFGLRXDRI || hasX11_EXTENSION_ATIFGLEXTENSION );
                     
                     if(DEBUG) {
-                        System.err.println("X11Util init OK "+isInitOK+"]"+
-                                           ", X11 Display(NULL) <"+nullDisplayName+">"+
-                                           ", XSynchronize Enabled: "+XSYNC_ENABLED);
+                        System.err.println("X11Util.initSingleton(): OK "+isInitOK+"]"+
+                                           ",\n\t X11 Display(NULL) <"+nullDisplayName+">"+
+                                           ",\n\t XSynchronize Enabled: " + XSYNC_ENABLED+
+                                           ",\n\t X11_EXTENSION_ATIFGLRXDRI " + hasX11_EXTENSION_ATIFGLRXDRI+
+                                           ",\n\t X11_EXTENSION_ATIFGLEXTENSION " + hasX11_EXTENSION_ATIFGLEXTENSION+
+                                           ",\n\t requiresToolkitLock "+requiresToolkitLock()+
+                                           ",\n\t requiresGlobalToolkitLock "+requiresGlobalToolkitLock()+
+                                           ",\n\t markAllDisplaysUnclosable "+getMarkAllDisplaysUnclosable()
+                                           );
                         // Thread.dumpStack();
                     }
                 }
@@ -147,6 +166,7 @@ public class X11Util {
      * <p>
      * Called by {@link NativeWindowFactory#shutdown()}
      * </p>
+     * @see ToolkitProperties
      */
     public static void shutdown() {
         if(isInit) {
@@ -189,8 +209,20 @@ public class X11Util {
         }
     }
     
-    public static boolean requiresToolkitLock() {
-        return true; // JAWT locking: yes, instead of native X11 locking w use a recursive lock.
+    /**
+     * Called by {@link NativeWindowFactory#initSingleton()}
+     * @see ToolkitProperties
+     */
+    public static final boolean requiresToolkitLock() {
+        return true; // JAWT locking: yes, instead of native X11 locking w use a recursive lock per display connection.
+    }
+    
+    /**
+     * Called by {@link NativeWindowFactory#initSingleton()}
+     * @see ToolkitProperties
+     */
+    public static final boolean requiresGlobalToolkitLock() {
+        return requiresGlobalToolkitLock; // JAWT locking: yes, instead of native X11 locking w use a global lock.
     }
     
     public static void setX11ErrorHandler(boolean onoff, boolean quiet) {
@@ -206,9 +238,6 @@ public class X11Util {
     public static boolean getMarkAllDisplaysUnclosable() {
         return markAllDisplaysUnclosable;
     }
-    public static void setMarkAllDisplaysUnclosable(boolean v) {
-        markAllDisplaysUnclosable = v;
-    }
     
     private X11Util() {}
 
@@ -373,7 +402,7 @@ public class X11Util {
         name = validateDisplayName(name);
         boolean reused = false;
         
-        synchronized(globalLock) {            
+        synchronized(globalLock) {
             for(int i=0; i<reusableDisplayList.size(); i++) {
                 if(reusableDisplayList.get(i).getName().equals(name)) {
                     namedDpy = reusableDisplayList.remove(i);
diff --git a/src/nativewindow/native/x11/Xmisc.c b/src/nativewindow/native/x11/Xmisc.c
index 9e2130668..8bfe28f2b 100644
--- a/src/nativewindow/native/x11/Xmisc.c
+++ b/src/nativewindow/native/x11/Xmisc.c
@@ -606,3 +606,38 @@ JNIEXPORT jobject JNICALL Java_jogamp_nativewindow_x11_X11Lib_GetRelativeLocatio
     return (*env)->NewObject(env, pointClz, pointCstr, (jint)dest_x, (jint)dest_y);
 }
 
+/*
+ * Class:     jogamp_nativewindow_x11_X11Lib
+ * Method:    QueryExtension0
+ * Signature: (JLjava/lang/String;)Z
+ */
+JNIEXPORT jboolean JNICALL Java_jogamp_nativewindow_x11_X11Lib_QueryExtension0
+  (JNIEnv *env, jclass unused, jlong jdisplay, jstring jextensionName)
+{
+    int32_t major_opcode, first_event, first_error;
+    jboolean res = JNI_FALSE;
+    Display * display = (Display *) (intptr_t) jdisplay;
+    const char* extensionName = NULL;
+
+    if(NULL==display) {
+        NativewindowCommon_throwNewRuntimeException(env, "NULL argument \"display\"");
+        return res;
+    }
+    if ( NULL == jextensionName ) {
+        NativewindowCommon_throwNewRuntimeException(env, "NULL argument \"extensionName\"");
+        return res;
+    }
+    extensionName = (*env)->GetStringUTFChars(env, jextensionName, (jboolean*)NULL);
+    if ( NULL == extensionName ) {
+        NativewindowCommon_throwNewRuntimeException(env, "Failed to get UTF-8 chars for argument \"extensionName\"");
+        return res;
+    }
+
+    res = True == XQueryExtension(display, extensionName, &major_opcode, &first_event, &first_error) ? JNI_TRUE : JNI_FALSE;
+
+    if ( NULL != jextensionName ) {
+        (*env)->ReleaseStringUTFChars(env, jextensionName, extensionName);
+    }
+    return res;
+}
+
diff --git a/src/test/com/jogamp/opengl/test/junit/jogl/acore/InitConcurrentBaseNEWT.java b/src/test/com/jogamp/opengl/test/junit/jogl/acore/InitConcurrentBaseNEWT.java
index 11d1331ed..6b2de8366 100644
--- a/src/test/com/jogamp/opengl/test/junit/jogl/acore/InitConcurrentBaseNEWT.java
+++ b/src/test/com/jogamp/opengl/test/junit/jogl/acore/InitConcurrentBaseNEWT.java
@@ -43,6 +43,7 @@ import com.jogamp.newt.Window;
 import com.jogamp.newt.opengl.GLWindow;
 import com.jogamp.opengl.test.junit.jogl.demos.es2.GearsES2;
 import com.jogamp.opengl.test.junit.util.UITestCase;
+import com.jogamp.opengl.test.junit.util.ValidateLockListener;
 import com.jogamp.opengl.util.Animator;
 
 /**
@@ -100,6 +101,7 @@ public class InitConcurrentBaseNEWT extends UITestCase {
             glWindow.setTitle("Task "+id);
             glWindow.setPosition(x + insets.getLeftWidth(), y + insets.getTopHeight() );
     
+            glWindow.addGLEventListener(new ValidateLockListener());
             glWindow.addGLEventListener(new GearsES2(0));
     
             Animator animator = new Animator(glWindow);
diff --git a/src/test/com/jogamp/opengl/test/junit/util/ValidateLockListener.java b/src/test/com/jogamp/opengl/test/junit/util/ValidateLockListener.java
new file mode 100644
index 000000000..73c1ad74c
--- /dev/null
+++ b/src/test/com/jogamp/opengl/test/junit/util/ValidateLockListener.java
@@ -0,0 +1,71 @@
+/**
+ * Copyright 2012 JogAmp Community. All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without modification, are
+ * permitted provided that the following conditions are met:
+ * 
+ *    1. Redistributions of source code must retain the above copyright notice, this list of
+ *       conditions and the following disclaimer.
+ * 
+ *    2. Redistributions in binary form must reproduce the above copyright notice, this list
+ *       of conditions and the following disclaimer in the documentation and/or other materials
+ *       provided with the distribution.
+ * 
+ * THIS SOFTWARE IS PROVIDED BY JogAmp Community ``AS IS'' AND ANY EXPRESS OR IMPLIED
+ * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND
+ * FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL JogAmp Community OR
+ * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
+ * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
+ * SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON
+ * ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
+ * NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF
+ * ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ * 
+ * The views and conclusions contained in the software and documentation are those of the
+ * authors and should not be interpreted as representing official policies, either expressed
+ * or implied, of JogAmp Community.
+ */
+ 
+package com.jogamp.opengl.test.junit.util;
+
+
+import javax.media.nativewindow.NativeSurface;
+import javax.media.opengl.GLAutoDrawable;
+import javax.media.opengl.GLEventListener;
+
+
+public class ValidateLockListener implements GLEventListener {
+
+    private void validateLock(GLAutoDrawable drawable) {
+        final NativeSurface ns = drawable.getNativeSurface();
+        ns.getGraphicsConfiguration().getScreen().getDevice().validateLocked();
+        
+        final Thread current = Thread.currentThread();
+        final Thread owner = ns.getSurfaceLockOwner();
+        if( ns.isSurfaceLockedByOtherThread() ) {
+            throw new RuntimeException(current.getName()+": Locked by another thread(1), owner "+owner+", "+ns);
+        }
+        if( current != owner ) {
+            if( null == owner ) {
+                throw new RuntimeException(current.getName()+": Not locked: "+ns);
+            }
+            throw new RuntimeException(current.getName()+": Locked by another thread(2), owner "+owner+", "+ns);            
+        }
+    }
+    
+    public void init(GLAutoDrawable drawable) {
+        validateLock(drawable);
+    }
+
+    public void reshape(GLAutoDrawable drawable, int x, int y, int width, int height) {
+        validateLock(drawable);
+    }
+
+    public void display(GLAutoDrawable drawable) {
+        validateLock(drawable);
+    }
+
+    public void dispose(GLAutoDrawable drawable) {
+        validateLock(drawable);
+    }
+}